High-sensitivity salinity measurement sensor based on no-core fiber

• Published in: Sensors and actuators. A. Physical. 2020-04, Vol.305, p.111947, Article 111947
• Main Authors: Lin, Zi-ting, Lv, Ri-qing, Zhao, Yong, Zheng, Hong-kun
• Format: Article
• Language: English
• Subjects: Fiber optics; Gaging; High sensitivity; Measurement; No-core fiber; Optical fiber sensor; Refractivity; Salinity; Seawater; Sensitivity; Sensitivity analysis; Sensors
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2020.111947

[Display omitted] •A SSNSS-based salinity sensing probe with high sensitivity of up to −3.42 nm/‰ (−16,310 nm/RIU) was proposed.•It has good fringe visibility and linearity which can reach more than 15 dB and 0.999 respectively.•It also has compact structure, good stability, simple manufacture and low cost. A compact, stable, low cost and high sensitivity fiber salinity sensor based on single mode fiber-single mode fiber-no-core fiber-single mode fiber-single mode fiber (SSNSS) structure is proposed and demonstrated. It is proved by experiments and simulations that the sensor has high sensitivity to external refractive index (RI) changes, so as to achieve the purpose of gauging the seawater salinity. When the RI of surrounding media in sensing area changes, the absolute value of sensitivity for the refractive index measurement can be above 16,000 nm/refractive index unit (RIU) that is higher than other fiber salinity sensors as we known. In the experimental study, a fiber salinity sensor with the sensitivity of up to -3.42 nm/‰ was achieved when the salinity varied between 0‰ and 40.001‰, and the sensor showed a good linear response.